JP2017013377A - Print data generation device and print data generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately reproduce anisotropic property of glossiness.SOLUTION: A print data generation device generates print data to reproduce an object having anisotropic glossiness. The print data generation device enters reflection property data representing reflection property of the object to be reproduced, then, an area to be coated with ink is divided into a plurality of areas representing the anisotropic property of glossiness according to the reflection property. Then, density data representing densities of color materials to be applied to respective divided areas are derived according to the reflection property of the object.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for reproducing gloss anisotropy that differs in appearance depending on an observation direction on a printed matter.

  In recent years, various methods have been proposed for recording printed matter with improved design properties by controlling the reflection characteristics of a printed image. Among them, a 3D printer is used to form a large number of minute concavo-convex structures, and metal ink and color ink are applied to the surface shape on which the fine concavo-convex structure is formed, thereby allowing diffusion color and gloss anisotropy. Has been proposed (Non-Patent Document 1).

"Bi-Scale Appearance Fabrication" ACM Transactions on Graphics (TOG)-SIGGRAPH 2013 Conference Proceedings TOG Homepage archive, Volume 32 Issue 4, July 2013

  Non-Patent Document 1 optimizes the density of metal and CMYKW color inks that minimize the error between the diffuse color to be recorded and the gloss anisotropy for the concavo-convex structure in one unit area. Calculated by Furthermore, the metal and each color ink are uniformly applied at the ink density calculated by the optimization process on the surface shape on which the minute concavo-convex structure is formed in one unit area. Here, the calculated ink density is an ink density that makes the diffusion color and gloss anisotropy in the unit area compatible as much as possible. However, when trying to reproduce the diffuse color and gloss anisotropy using the ink density, the recording accuracy of the gloss anisotropy decreases because the diffuse color and the gloss anisotropy are in a trade-off relationship. There was a problem to do. Further, since each ink is uniformly applied to the concavo-convex structure in one unit area, it is necessary to control the gloss anisotropy only by the surface shape. Therefore, like satin embroidery, it is difficult to record gloss anisotropy with high accuracy in the direction of texture, with high image clarity, and in the direction perpendicular to the texture, low image clarity and high color development. It was.

  A print data generation apparatus according to the present invention is a print data generation apparatus that generates print data for reproducing printed matter having gloss anisotropy, and inputs reflection characteristic data indicating reflection characteristics of an object to be reproduced. An input unit, a dividing unit that divides an ink application region into a plurality of regions expressing gloss anisotropy according to the reflection characteristics, and a plurality of regions divided by the dividing unit Density data deriving means for deriving density data indicating the density of the color material to be applied according to the reflection characteristics of the object, and surface shape data indicating the surface shape of the area where the ink is applied according to the reflection characteristics of the object. And surface shape data deriving means for deriving.

  According to the present invention, gloss anisotropy having different image clarity and color developability depending on the observation direction can be recorded with high accuracy.

FIG. 6 is a diagram illustrating an object reproduced in the first embodiment. 1 is a system configuration diagram of Embodiment 1. FIG. 1 is a block diagram of an image recording apparatus according to Embodiment 1. FIG. 3 is a flowchart showing the operation of the first embodiment. 6 is a conceptual diagram of reflection characteristic data input in Example 1. FIG. 3 is a conceptual diagram of surface shape initial data input in Example 1. FIG. It is explanatory drawing of the solid angle area | region of the light source direction of Example 1, and an observation direction. 3 is a flowchart illustrating an operation of an ink application area dividing unit according to the first exemplary embodiment. 6 is an explanatory diagram of an ink application area dividing process according to Embodiment 1. FIG. 6 is an explanatory diagram of an ink application area dividing process according to Embodiment 1. FIG. 6 is a flowchart illustrating an operation of an ink density data deriving unit according to the first exemplary embodiment. 6 is a diagram illustrating an example of ink density initial data input in Embodiment 1. FIG. It is a figure explaining the shielding data of the surface shape calculated in Example 1. FIG. 6 is a diagram illustrating an example of ink density data derived in Embodiment 1. FIG. It is a conceptual diagram of the surface shape data derived | led-out in Example 1, and an ink application | coating area | region. FIG. 6 is a diagram illustrating an example of ink density data calculated by the iterative calculation process of the first embodiment. 6 is a block diagram of an image recording apparatus according to Embodiment 2. FIG. 6 is a flowchart showing the operation of the second embodiment. FIG. 10 is a diagram illustrating an example of surface shape data, an ink application region image, and ink density data calculated by repetitive calculation processing according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the present invention, and all the combinations of features described in the present embodiment are not necessarily essential to the solution means of the present invention.

[Example 1]
In this embodiment, as shown in FIG. 1, the reflection characteristics of a woven fabric with satin embroidery on the left side and weft on the right side are expressed by controlling the surface shape and the color corresponding to the ink on the medium. Hereinafter, an object that expresses reflection characteristics (in this embodiment, satin embroidery) is referred to as an object. Here, in order to simplify the description, an example will be described in which an object is roughly divided into two regions having different reflection characteristics as shown in FIG.

  In the following embodiments, the ink application area on the medium surface is divided into a plurality of areas according to the gloss anisotropy, and the divided areas in the ink application area are applied with different ink concentrations. Thus, an example will be described in which gloss anisotropy with different image clarity and color developability depending on the viewing direction is recorded with high accuracy.

  FIG. 2 is a diagram showing a system configuration of the image recording apparatus 208 in the present embodiment. The CPU 201 uses the RAM 203 as a work memory, executes an operating system (OS) and various programs stored in a ROM 202, a hard disk drive (HDD) 212, and various recording media, and controls each configuration via a system bus 207. Note that the programs executed by the CPU 201 include programs such as image processing to be described later. A general-purpose interface (I / F) 204 is a serial bus interface such as USB, and is connected to a printer 210 and an input device 211 such as a mouse and a keyboard via a serial bus 209. The serial ATA (SATA) I / F 205 is connected to a general-purpose drive 213 that reads and writes the HDD 212 and various recording media. The CPU 201 uses various recording media mounted on the HDD 212 and the general-purpose drive 213 as data storage locations for reading and writing. A video card (VC) 206 is a video interface to which a display 214 is connected. The CPU 201 displays a user interface (UI) provided by the program on the display 214 and receives user input including user instructions via the input device 211.

  In addition, although there are other components of the apparatus, the description is omitted because it is not the main point of the present embodiment.

  Here, the image recording apparatus 208 including the printer 210 has been described as an example, but a print data generation apparatus not including the printer 210 may be configured. That is, a print data generation device that can generate print data for expressing gloss anisotropy as described later and output the generated print data to the printer 210 may be used. Then, the printer 210 may perform printing based on the output print data. In this embodiment, the printer 210 will be described by taking an ink jet printer using a resin that is cured by ultraviolet irradiation as an example.

  FIG. 3 is a functional block diagram showing an embodiment of the image recording apparatus 208 in the present embodiment. The image recording apparatus 208 includes a reflection characteristic data input unit 301, an ink application area dividing unit 303, an ink density data deriving unit 304, and a surface shape data deriving unit 305. In addition, an ink application area data holding unit 306, an ink density data holding unit 307, a surface shape data holding unit 308, a print data deriving unit 309, an image recording unit 310, and a control unit 311 are provided.

  The reflection characteristic data input unit 301 inputs reflection characteristic data of an object. The input reflection characteristic data may be data transmitted from an external device, data stored in the image recording device 208, or data input from a user via a UI or the like. The input reflection characteristic data is output to the ink application area dividing unit 303, the ink density data deriving unit 304, and the surface shape data deriving unit 305. In this embodiment, the reflection characteristic data of the object as shown in FIG. 1 is input. The reflection characteristic data is two-dimensional discrete image data as will be described later, and BRDF (bidirectional reflectance distribution function) indicating diffusion color and gloss anisotropy for each unit region (hereinafter referred to as a pixel). Has the parameters of the modeled function. In order to reproduce the BRDF of each pixel, a surface shape having, for example, 20 × 20 lattice points is formed in the media region corresponding to one pixel.

  The surface shape data holding unit 308 holds surface shape data to be recorded in each area on the medium. The surface shape data is data representing the unevenness formed on the medium in order to realize the reflection characteristics desired to be expressed. Each pixel in the surface shape data stores height information indicating the height. Specifically, it consists of pixel values for each pixel obtained by dividing an area in the medium corresponding to the reflection characteristic for one pixel to be expressed into 20 × 20 grid points. In this embodiment, as will be described later, processing for deriving surface shape data, ink density data, and the like for reproducing reflection characteristics indicated by input reflection characteristic data by optimization processing is performed. The surface shape data held in the surface shape data holding unit 308 is sequentially updated by the surface shape data derived by the surface shape data deriving unit 305 described later. The surface shape data held in the surface shape data holding unit 308 is sequentially rewritten until the optimization process is completed. Since the optimization process sequentially rewrites the surface shape data generated based on the input reflection characteristic data, the surface shape data initially held in the surface shape data holding unit 308 is an arbitrary shape. The data can be.

  The surface shape initial data acquisition unit 302 acquires the surface shape data held in the surface shape data holding unit 308 as the surface shape initial data. The surface shape initial data is surface shape data used as input data in the optimization process described above. Therefore, in the process of the first step of the optimization process, data of an arbitrary shape held in the surface shape data holding unit 308 is used. In the subsequent processing in the optimization processing, the surface shape data derived by the surface shape data deriving unit 305 (to be described later) held in the surface shape data holding unit 308 is acquired as the surface shape initial data.

  The ink application region dividing unit 303 divides the ink application region into a plurality of regions based on the surface shape initial data acquired by the surface shape initial data acquisition unit 302 and the reflection characteristic data of the object input from the reflection characteristic data input unit 301. Divide into The ink application area dividing unit 303 basically divides the ink application area based on the initial surface shape data. For example, as described above, in order to reproduce BRDF for one pixel in the reflection characteristic data, a surface shape having 20 × 20 lattice points is formed. One of the parameters included in the reflection characteristic data input as described later when dividing the region of 20 × 20 grid points into an ink application region corresponding to one pixel and dividing the region into a plurality of regions. The ink application area is divided using a certain rotation angle. The ink application area dividing unit 303 divides an ink application area corresponding to one pixel into an area in which ink corresponding to the diffusion color is applied, an area in which ink according to the gloss image property in the X direction is applied, and an area in the Y direction. The area is divided into areas where ink is applied according to the gloss image clarity. Details will be described later. The ink application region dividing unit 303 outputs data indicating the divided ink application regions to the ink density data deriving unit 304, the surface shape data deriving unit 305, and the ink application region data holding unit 306.

  The ink density data deriving unit 304 acquires the surface shape initial data acquired by the surface shape initial data acquiring unit 302. Also, data indicating the ink application area divided by the ink application area dividing unit 303 and reflection characteristic data of the object are acquired. Based on the acquired data, ink density data for recording an image on the medium is derived. That is, the ink density data deriving unit 304 derives the ink density applied to each divided area. The ink density data deriving unit 304 derives the ink density for each ink application region based on the reflection characteristic data of the object. For example, for each ink application region of the surface shape data for one pixel, an ink density that approximates the reflection characteristics when ink is applied at the ink density of each ink and the reflection characteristics of the reflection characteristic data of the object is derived. . Details will be described later. The ink density data deriving unit 304 outputs the derived ink density data to the surface shape data deriving unit 305 and the ink density data holding unit 307.

  The surface shape data deriving unit 305 acquires the above-described surface shape initial data, data indicating the divided ink application areas, derived ink density data, and object reflection characteristic data. Based on the acquired data, surface shape data to be recorded on the medium is derived. The surface shape data deriving unit 305 derives surface shape data for reproducing the reflection characteristic data of the object. The surface shape data deriving unit 305, for example, the reflection characteristics when ink is applied at the ink density acquired for each ink application region of the surface shape initial data acquired for one pixel, and the reflection characteristics of the object reflection characteristic data Deriving surface shape data that approaches Details will be described later. The surface shape data deriving unit 305 outputs the derived surface shape data to the surface shape data holding unit 308. In addition, since the reflection characteristics change according to the ink density, the surface shape initial data acquired by the surface shape initial data acquisition unit 302 and the derived surface shape data may change. In the subsequent processing in the optimization processing, the derived surface shape data is acquired by the surface shape initial data acquisition unit 302 as the surface shape initial data.

  The print data deriving unit 309 includes data indicating the ink application area stored in the ink application area data holding unit 306, ink density data stored in the ink density data holding unit 307, and the surface stored in the surface shape data holding unit 308. Print data is derived from the shape data. The derived print data is output to the image recording unit 310. The image recording unit 310 drives the printer 210 from the print data calculated by the print data deriving unit 309 to record an image on a medium. The control unit 311 controls the entire process.

<Operation of Image Recording Device 208>
FIG. 4 is a flowchart showing the image recording method of this embodiment. More specifically, after a computer-executable program describing the procedure shown in the flowchart of FIG. 4 is read from the ROM 202 onto the RAM 203, the CPU 201 executes the program to execute the process.

  Hereinafter, each process shown in FIG. 4 will be described. In step S401, the reflection characteristic data input unit 301 inputs the reflection characteristic data of the object. Here, the reflection characteristic data input to the reflection characteristic data input unit 301 will be described. The reflection characteristic data is two-dimensional discrete image data as described above, and is a parameter of a function that models a BRDF (bidirectional reflectance distribution function) indicating diffusion color and gloss anisotropy for each pixel. have. In this embodiment, the anisotropic Ward model represented by the following equations (1) and (2) is used as the BRDF model. The BRDF model is not limited to the one described in the present embodiment, and any model can be used as long as it can express the diffuse color and the gloss anisotropy.

Here, ω _i is a light source vector indicating the direction of the light source, and ω _o is a line-of-sight vector indicating the direction of the line of sight. θ _i is the elevation angle formed by the pixel normal vector n and the light source vector ω _i , θ _o is the elevation angle formed by the pixel normal vector n and the line-of-sight vector ω _o , θ _h is the pixel normal vector n and the light source This is the elevation angle formed by the vector ω _i and the half vector h of the line-of-sight vector ω _o . Φ _h is an azimuth angle formed by the half vector h and the tangent vector (x axis) of the pixel. ρ _d is a diffuse color intensity, ρ _s is a gloss color intensity, α _x is a gloss map property in the tangent vector direction due to specular reflection, and α _y is a parameter representing a gloss map property in the vertical normal vector direction due to specular reflection. . The gloss anisotropy is expressed by expressing the gloss image clarity in two dimensions in the tangential vector direction (x axis) and the vertical normal vector direction (y axis).

In this embodiment, each unit area (pixel) has the above four parameters (ρ _d , ρ _s , α _x , α _y ), and these four parameters are R (red) and G (green). , B (blue) have a value for each of the three colors. The tangent vector (x-axis) can be defined so that the direction is different for each pixel, and has a rotation angle φ between each pixel and the horizontal axis of the two-dimensional image plane for each pixel. As described above, in this embodiment, the reflection characteristic data includes four parameters (ρ _d , ρ _s , α _x , α _y ) × 3 colors (R, G, B) +1 (rotation angle φ) in each pixel. It has image data composed of a total of 13 channels. Each image data is 8-bit data. That is, data in which each parameter is represented as 8-bit image data is input as reflection characteristic data.

FIG. 5 is a diagram showing an example of part of the reflection characteristic data input in this embodiment. The reflection characteristic data in FIG. 5 is data indicating the reflection characteristic of the object shown in FIG. 5A to 5E show four G (green) component channels (ρ _d , ρ _s , α _x , α _y ) of the reflection characteristic data composed of 13 channels, the rotation angle φ, and the like. Is an example of image data that is displayed in gray scale according to the pixel value. FIG. 5A shows the image data of the G component diffusion color ρ _d channel, and pixel values 0 to 255 are assigned to the diffusion color ρ _d = 0 to 1. Note that ρ _d = 0 indicates that there is no diffuse color, and ρ _d = 1 indicates that there is all the diffuse color (strong intensity). Values between 0 and 1 indicate the intensity scale of the diffuse color ρ _d . FIG. 5B shows image data of the glossy color ρ _s channel, and pixel values 0 to 255 are assigned to the glossy color ρ _s = 0 to 1. FIG. 5 (c) is the image data in the x direction of the gloss image clarity alpha _x, pixel values 0 to 255 are assigned to the x-direction of the gloss image clarity alpha _x = 0 to 1. Figure 5 (d) is an image data of a gloss image clarity alpha _y in the y direction, the pixel values 0 to 255 are assigned to y-direction of the gloss image clarity alpha _y = 0 to 1. FIG. 5E shows image data representing the rotation angle φ between the tangent vector and the horizontal axis of the two-dimensional image plane. Pixel values 0 to 255 are assigned to the rotation angle φ = 0 ° to 180 °. ing.

  A pixel value corresponding to the reflection characteristic is stored in each pixel of the image data. For example, the left region 1 having anisotropic gloss with high image clarity in the x direction and low image clarity in the y direction has a dark gray color with a pixel value of 64 in FIG. 5C and a pixel value of 192 in FIG. It is light gray. Further, the right area 2 having an anisotropic gloss with a high image clarity in the x direction and a low image clarity in the y direction and an angle of rotation φ = 90 ° is shown in FIGS. 5 (c) and 5 (d) respectively. The pixel value 64 is dark gray, the pixel value 192 is light gray, and in FIG. 5E, the pixel value 128 is gray. The input reflection characteristic data is stored in a storage area such as the ROM 202 or the RAM 203. In the example of FIG. 5, the reflection characteristic data of the object of FIG. 1 will be described by taking an example of data indicating a region where the mapping property in the x direction and the mapping property in the y direction are the same and the rotation angle is different. did. However, for example, reflection characteristic data having the same rotation angle and different image clarity in the x direction and image clarity in the y direction may be used.

In step S402, the surface shape initial data acquisition unit 302 inputs the surface shape data stored in the surface shape data holding unit 308 as the surface shape initial data. In this embodiment, the reflection characteristic of the object is expressed by controlling the height of the 20 × 20 lattice point L arranged for one pixel of the reflection characteristic data. However, the height of the lattice point L can be controlled even if a subsequent rotation process is performed on the rotation angle φ of the reflection characteristic data. Therefore, 8-bit image data composed of 29 × 29 grid point L height information is used as the surface shape initial data for an area 1.45 (> √2) times as large as one pixel of the object. Accordingly, the surface shape initial data acquisition unit 302 is configured with the height information of the 29 × 29 lattice points L by changing the height of the 20 × 20 lattice points L stored in the surface shape data holding unit 308 as necessary. Convert to data and obtain as surface shape initial data. Pixel values 0 to 255 are assigned to, for example, a height 0 to 255 μm of the grid point L on each pixel position. FIG. 6 is an example of the initial surface shape data for one pixel of the initial surface shape data, and has a height according to a Gaussian distribution centered at the center of the image. The surface shape initial data is sequentially changed by an optimization process described later. FIG. 6 shows an example of data acquired by the surface shape initial data acquisition unit 302 first. The surface shape initial data acquisition unit 302 stores the acquired surface shape initial data H ^p ₀ of the pixel p in a predetermined storage area. The surface shape initial data acquisition unit 302 acquires data for all pixels corresponding to the reflection characteristic data.

  In step S403, the ink application area dividing unit 303 corresponds one pixel area to each component of the reflection characteristic data for each pixel from the reflection characteristic data input in step S401 and the initial surface shape data acquired in step S402. The ink application area is divided. Specifically, an area corresponding to one pixel is defined as an ink application area that expresses a diffusion color of reflection characteristic data, an ink application area that expresses glossy color in the x direction and image clarity, and a glossy color and mapping in the y direction. The ink is divided into ink application areas that express characteristics. Details of the ink application area dividing process will be described later. Data indicating the divided ink application area is stored in the ink application area data holding unit 306.

  In step S404, the ink density data deriving unit 304 acquires the reflection characteristic data input in step S401, the surface shape initial data acquired in step S402, and the ink application region data derived in step S403. From the acquired data, ink density data representing each component of the reflection characteristic data is derived for each pixel. Specifically, the ink density data is derived for the ink application region for each component of the reflection characteristic data divided in step S403. Details of the ink density data calculation processing will be described later with reference to FIG. The derived ink density data is stored in the ink density data holding unit 307.

  In step S405, the surface shape data deriving unit 305 determines the surface for each pixel from the input reflection characteristic data, the acquired surface shape initial data, the data indicating the derived ink application area, and the derived ink density data. Deriving shape data. Details of the surface shape data derivation process will be described later. The derived surface shape data is stored in the surface shape data holding unit 308.

  In step S406, the control unit 311 acquires data indicating the ink application region obtained in step S403, ink density data derived in step S404, and surface shape data derived in step S405. Then, it is determined using the evaluation function described in Non-Patent Document 1, for example, whether the reflection characteristic data of the printed matter derived from these data represents the reflection characteristic data of the object input in step S401. Specifically, it is determined whether the reflection characteristic data of the printed material based on the print data satisfies the following expression (3) with respect to the reflection characteristic data of each pixel of the object to be reproduced.

E ^p is a function for evaluating the difference between the reflection characteristic of the object based on the input reflection characteristic data and the reflection characteristic of the printed matter based on the derived print data for the pixel p. I _brdf is a reflection characteristic (BRDF) derived from the reflection characteristic data of the input object according to the equation (1). _I′brdf is the reflection characteristic (BRDF) of the printed matter at the pixel p derived from the ink application area data, ink density data, and surface shape data obtained in each step. ρ ^p _d and ρ ^p _s are parameters of diffuse color and gloss color at the pixel p. α ^p _x and α ^p _y are parameters of gloss image clarity of the pixel p in the x and y directions. φ ^p is a parameter of the rotation angle φ at the pixel p. n ^p is the surface normal vector of the object at pixel p. H ^p , R ^p , and D ^p are surface shape data, ink application area, and ink density data for the pixel p. In Expression (3), the difference between the BRDF of the object and the BRDF of the printed material for various light sources and observation directions is integrated, and it is determined whether the integrated value is less than a predetermined threshold (less than Δ), thereby determining the ink application region and the ink density. The end of derivation of the surface shape data is determined. Ω ^p _L and Ω ^p _V are solid angle regions in the light source direction and the observation direction in the pixel p used for determination. In this embodiment, Ω ^p _L and Ω ^p _V are discrete light sources and observation directions as shown in FIG. 7, and it is determined whether or not the sum of the BRDF differences in each light source and observation direction is less than a threshold value Δ. Details of the method for deriving _I′brdf will be described later.

  When the expression (3) is satisfied for all pixels, the control unit 311 determines that the ink application region, the ink density data, and the surface shape data representing the reflection characteristics of the object have been derived, and the process proceeds to step S407. On the other hand, when there is a pixel that does not satisfy Expression (3), the control unit 311 returns the process to step S402 and repeats the derivation process. When the process returns from step S407 to step S402, the initial surface shape data acquired in step S402 is the surface shape data derived in step S405. Thus, each data suitable for the reflection characteristic data input by the optimization process that repeats the process is derived.

In step S407, the print data deriving unit 309 derives print data for recording the surface shape and the ink layer by the printer 210 from the surface shape data, the ink application area, and the ink density data determined so far. For the surface shape, the ink density and the number of ink overlays necessary for recording the height of the surface shape data derived in step S405 are derived for each pixel. In this embodiment, clear ink is used for recording the surface shape. Thereafter, the ink density data used for recording the surface shape and the ink layer is converted into binary data indicating ON / OFF of ink dot recording by halftone processing. For these treatments, known techniques used for general ink jet printing can be used. Therefore, detailed description here is omitted. The derived print data is stored in a predetermined storage area. In step S408, the image recording unit 310 drives the printer 210 from the print data derived in step S407, records an image on the medium, and ends the process.
<Operation of Ink Application Region Dividing Unit 303>
Hereinafter, details of the ink application region dividing process in step S403 will be described with reference to the flowchart of FIG. In step S801, the ink application area dividing unit 303 converts the 29 × 29 lattice point L (x, y) of the surface shape initial data H ^p ₀ input in step S402 to a rotation angle φ in the direction opposite to the rotation angle of the reflection characteristic data. Lattice point L ′ (x ′, y ′) rotated by the distance is calculated (formula (4)). The pixel of the surface shape initial data H ^p ₀ corresponding to a pixel whose reflection characteristic data rotation angle is not 0 is a pixel in which the rotation of φ has already been reflected. In this process, since the process of obtaining the boundary portion of the height using a differential filter in the X direction or a differential filter in the Y direction is performed in the process described later, the process is rotated in the reverse direction to unify the directions.

  FIG. 9A shows the acquired surface shape initial data, and FIG. 9B shows the reverse rotation data of the surface shape rotated in the reverse direction with respect to the tangent direction φ. In the present embodiment, the initial surface shape data acquired at the beginning of the processing of FIG. 4 has the height of an isotropic Gaussian distribution centered at the center of the pixel p region. b) is the same data. The reverse rotation data of the calculated surface shape is stored in a predetermined storage area.

In step S802, the ink application region dividing unit 303 convolves a differential filter in the x direction with the reverse rotation data of the surface shape calculated in step S801. FIG. 9C shows a 3 × 3 differential filter in the x direction to be convolved, and FIG. 9D shows x direction differential data dH _x of the surface shape calculated by the filter convolution. Scale conversion is performed so that the pixel value becomes 128 when the calculated value is 0. The ink application area dividing unit 303 stores the x-direction differential data dH _x of the calculated surface shape in a predetermined storage area. In step S803, the ink application region dividing unit 303 convolves a y-direction differential filter with the surface shape reverse rotation data calculated in step S801. FIG. 9E is a 3 × 3 differential filter in the y direction to be convolved, and FIG. 9F is the y direction differential data dH _y of the surface shape calculated by the filter convolution. Scale conversion is performed so that the pixel value becomes 128 when the calculated value is 0. The ink application area dividing unit 303 stores the calculated y-direction differential data dH _y of the surface shape in a predetermined storage area.

In step S804, the ink application area dividing unit 303 uses the surface shape x-direction differential data dH _x and y-direction differential data dH _y calculated in steps S802 and S803 in accordance with the following equation (5) to determine the diffusion color ink application area. R ^p _d is calculated.

In equation (5), x of the surface shape of each grid point L 'rotated by the rotation angle φ in the opposite direction, by binarizing the y direction differential data with a predetermined threshold value delta _d, diffuse color ink coating area R ^p _d is calculated. Expression (5) performs processing for obtaining a common part of the x-direction differential data and the y-direction differential data, and thereby a region corresponding to a flat portion of the surface shape is calculated. FIG. 10A shows the diffusion color ink application area calculated according to the equation (5), and the white area of the pixel value 255 is the diffusion color ink application area. The calculated diffusion color ink application area is stored in a predetermined storage area.

In step S805, the ink application region dividing unit 303 calculates the following equation (6) from the surface shape x and y direction differential data dH _x and dH _y calculated in steps S802 to S804 and the diffused color ink application region R ^p _d. Accordingly, the glossy image ink application region R ^p _x in the x direction is calculated.

By performing binarization processing on each lattice point L ′ rotated in the opposite direction by the rotation angle φ based on the diffusion color ink application region and the x and y direction differential data of the surface shape, the gloss image-rendering ink application region R in the x direction. ^p _x is calculated. Expression (6) is a region that is not the diffused color ink application region R ^p _d , and performs processing for obtaining a portion where the value of the x-direction differential data is large, thereby changing the height of the surface shape in the x-direction. The area to be calculated is calculated. FIG. 10B shows the glossy image ink application area in the x direction calculated according to the equation (6), and the white area having the pixel value 255 is the glossy image ink application area in the x direction. The calculated gloss image ink application area data in the x direction is stored in a predetermined storage area.

In step S806, the ink application area dividing unit 303 uses the surface shape x, y direction differential data calculated in steps S802, S803, and S804 and the diffusion color ink application area R ^p _{d according} to the following equation (7). calculating a gloss image clarity inked areas in the y direction R ^p _y.

By applying binarization processing to each lattice point L ′ rotated in the opposite direction by the rotation angle φ based on the diffusion color ink application region and the x and y direction differential data of the surface shape, the gloss image-rendering ink application region R in the y direction. ^p _y is calculated. Expression (7) is a region that is not the diffused color ink application region R ^p _d , and performs processing for obtaining a portion where the value of the y-direction differential data is large, thereby changing the height of the surface shape in the y-direction. The area to be calculated is calculated. FIG. 10C shows the y-direction glossy image ink application area calculated according to the equation (7), and the white area with the pixel value 255 is the y-direction glossy image ink application area. The calculated gloss image ink application area data in the y direction is stored in a predetermined storage area.

  In step S807, the ink application region dividing unit 303 is the same as the tangent direction of the reflection characteristic data with respect to the 29 × 29 lattice point L ′ (x ′, y ′) of each ink application region according to the following equation (8). A lattice point L ″ (x ″, y ″) rotated by φ in the direction is calculated.

After the rotation processing, trimming is performed on a 20 × 20 lattice point region in the pixel p region with respect to the diffuse color, glossy image properties in the x direction, and the y direction. By rotating and trimming in the forward direction, the ink application regions for the 20 × 20 grid points of the diffuse color, the gloss image property in the x direction, and the gloss image property in the y direction are calculated. In the present embodiment, it is assumed that the ink application region R ^p ₁ shown in FIGS. 10D to 10F is calculated. The calculated forward rotation data of the ink application area is stored in the ink application area data holding unit 306 as the ink application area R ^p (= R ^p ₁ ). In other words, the ink application region R ^p ₁ is used as a generic parameter for the diffused color ink application region, the x direction glossy image application region, and the y direction glossy image application region.

By performing the above processing for each pixel, the surface shape of the object can be divided into regions to which the glossy color inks in the diffusion color, x direction, and y direction are applied. In this embodiment, the initial surface shape data having the same isotropic Gaussian distribution height is input for all the pixels in the first processing of FIG. 4, so FIGS. Ink application region R ^p ₁ shown in FIG.

<Operation of Ink Density Data Deriving Unit 304>
Hereinafter, details of the ink density data deriving process in step S404 will be described with reference to the flowchart of FIG. The ink density data deriving unit 304 derives the ink density of each ink application area divided in step S403. Here, the reflection characteristics when ink is output at a certain ink density to each divided ink application area in the surface shape acquired in step S402 and the reflection characteristics of the reflection characteristic data input in step S401 are close to each other. Processing for determining the ink density is performed. Of course, there are few cases where final ink density data is derived only by the process of step S404 for the first time. Accordingly, step S404 is executed according to the surface shape initial data acquired again in step S402 via step S406, and ink density data is derived each time.

In step S1101, the ink density data deriving unit 304 inputs the ink density data stored in the ink density data holding unit 307 as ink density initial data. In this embodiment, each ink density data shown in FIG. 12 is stored in the ink density data holding unit 307 for each component of the diffusion color ink D _d0 , the glossy image ink D _{x0 in} the x direction, and the gloss image ink D _{y0 in} the y direction. It is stored as the ink density initial data D _0. The input ink density initial data is stored in a predetermined storage area. The initial ink density data may be data in which an arbitrary ink density is defined, and may not be the example of FIG.

  In step S1102, the ink density data deriving unit 304 determines the surface shape with respect to a predetermined light source / line-of-sight direction of illumination from the initial surface shape data acquired in step S402 according to the following equation (9) described in Non-Patent Document 1. Calculate whether each grid point in the data is occluded. This is because the ink density changes in the shielded area.

f is the f-th polygon in the 38 × 38 polygon generated by trimming the surface shape initial data H ^p ₀ in the 20 × 20 lattice point L region in the pixel p region and forming a triangular polygon. . A (f) is an area of the polygon f. V (q, ω _o ) and V (q, ω _i ) are shielding functions at a point q in the polygon f region with respect to the line-of-sight direction and the light source direction, and are 1 when viewed from the line-of-sight direction and 0 when not visible. . In this embodiment, the shielding data for each polygon in the surface shape data is calculated according to the equation (9) for the discrete light source / line-of-sight directions shown in FIG. Expression (9) obtains a value indicating the shielding state of the point q included in the polygon f when the lattice points of a certain pixel P in the surface shape initial data are converted into polygons for all the points included in the polygon f. This process is performed for each polygon.

  FIG. 13 shows the shielding data calculated for each direction shown in FIG. 7. The shielded polygon area is black, and the unshielded polygon area is white. The calculated data is stored in a predetermined storage area as surface shape shielding data.

In step S1103, the ink density data deriving unit 304 acquires data indicating the ink application region divided in step S403, surface shape shielding data calculated in step S1102, and surface shape initial data acquired in step S402. From these data, the diffusion color ink density data D ^p _d of the pixel p is calculated according to the following equation (10).

Ω ^p _L and Ω ^p _V are solid angle regions in the light source direction and the observation direction in the pixel p, which are used when calculating the diffusion color ink density data. In this embodiment, diffusion color ink density data equal to the reflection characteristic data input in the discrete light source / line-of-sight directions shown in FIG. 7 is calculated. More specifically, the diffused ink density data D ^p that reduces the difference between the reflection characteristic (I _brdf ) of the reflection characteristic data input in step S 401 and the reflection characteristic (I ′ _brdf ) obtained from each of the above data. _d is calculated. R ^p is an ink application region in the pixel p. In this embodiment, the ink application region R ^p = R ^p ₁ divided in step S403 is fixed. D ^p _k is ink density data for each component k of the reflection characteristic data at the pixel p. k is an index representing the diffused color d, the gloss image x in the x direction, and the gloss image y in the y direction. In this embodiment, D ^p _x = D ^p _x0 and D ^p _y = D ^p _y0 are fixed. In other words, when calculating the diffusion color ink density data D ^p _d , the ink density of the glossy image property in the x direction and the glossy image property in the y direction are fixed to the initial ink density data input in step S1101. H ^p is surface shape data in the pixel p. In this embodiment, H ^p = H ^p ₀ is fixed. That is, the surface shape data is fixed to the surface shape initial data acquired in step S402.

Then, the diffusion color ink density data D ^p _d is calculated by using the diffusion color ink density initial data D ^p _d0 input in step S1101 as an initial value and using a known optimization algorithm such as a gradient method or quadratic programming. To do. Further, I ′ _brdf is calculated according to the following equation (11).

_I′brdf represents the reflection characteristic (BRDF) when a certain ink amount (ink density data D ^p _k ) is output to the region of the pixel p (ink application region R ^p , surface shape data H ^p ). In the equation (11, the reflection characteristic considering the shielding region is obtained for each polygon in the pixel p. _If is the BRDF of the polygon f, n _f is the surface normal of the polygon f, γ _f is the light source direction, and the line of sight a shielding section of the polygon f with respect to the direction .A (H ^p, ω _o) are among the pixels p region is the area obtained by projecting a region visible from viewing direction in the viewing direction. Further, I _f the following formula (12 ).

R ^p (L (f), k) is a k-component ink application region for the lattice point L in the pixel p. If the ink expressing the reflection characteristic of the k component is applied to the lattice point L, 1 is not applied. In this case, it becomes 0. L (f) is a function for calculating the nearest lattice point L of the polygon f. ρ ^LUT _d and ρ ^LUT _s are the intensity of the diffuse color and glossy color with respect to the ink density. Further, α ^LUT _x and α ^LUT _y are the gloss image property in the x direction and the gloss image property in the y direction with respect to the ink density, and in this embodiment, refer to a look-up table in which each BRDF parameter for the ink density is stored in advance. Calculated by A (H ^p , ω _o ) is calculated according to the following equation (13) described in Non-Patent Document 1.

A (f) is a plane area on the polygon f. Diffusion color ink density data is calculated according to the above equations (10) to (13). In this embodiment, it is assumed that the calculated diffusion color ink density data is D ^p _d = D ^p _d1 . The calculated diffusion color ink density data D ^p _d1 is stored in a predetermined storage area.

In step S1104, the ink density data deriving unit 304 adds the diffusion color ink density data calculated in step S1103 to the data described in step S1103, and the glossy image ink density data in the x direction according to the following equation (14). D ^p _x is calculated.

Equation (14) is an x-direction glossy image _{clarity in} which the difference between the reflection characteristic (I _brdf ) of the reflection characteristic data input in step S 401 and the reflection characteristic (I ′ _brdf ) obtained from each of the data is small. calculating the ink density data D ^p _x. Of the parameters of the equation (14), the difference from the equation (10) is the diffusion ink color density data. The other parameters are the same as those described in Expression (10). In Expression (14), the diffusion color ink density is fixed to the diffusion color ink density data D ^p _d = D ^p _d1 in the pixel p calculated in step S1103.

Then, by using a glossy image property ink density initial data D ^p _x0 in the x direction input in step S1101 as an initial value and using a known optimization algorithm such as a gradient method or quadratic programming method, the gloss image property in the x direction is obtained. calculating the ink density data D ^p _x. In the present embodiment, it is assumed that the calculated gloss image ink density data D ^p _x = D ^p _x1 in the x direction. The calculated gloss image ink density data D ^p _x1 in the x direction is stored in a predetermined storage area.

In step S1105, the ink density data deriving unit 304 adds the diffusion color ink density data calculated in step S1103 and the glossy image ink density data in the x direction calculated in step S1104 to the data described in step S1103. Then, according to the following equation (15), calculates a gloss image clarity ink density in the y-direction data D ^p _y.

Equation (15) is a y-direction glossy image _{clarity in} which the difference between the reflection characteristic (I _brdf ) of the reflection characteristic data input in step S 401 and the reflection characteristic (I ′ _brdf ) obtained from each of the data is small. calculating the ink density data D ^p _y. Among the parameters of the equation (15), the difference from the equation (10) is the diffusion ink color density data and the gloss image ink density data in the x direction. The other parameters are the same as those described in Expression (10). In Expression (15), the diffusion color ink density is fixed to the diffusion color ink density data D ^p _d = D ^p _d1 in the pixel p calculated in step S1103. The gloss image ink density in the x direction is fixed to the gloss image ink density data D ^p _x = D ^p _x1 in the x direction at the pixel p calculated in step S1104. Then, using the y-direction glossy image density ink density initial data D ^p _y0 input in step S1101 as an initial value, a known optimization algorithm such as a gradient method or quadratic programming is used, so that the y-direction glossy imageability is obtained. calculating the ink density data D ^p _y. In this embodiment, it is assumed that the calculated gloss image ink density data D ^p _y = D ^p _y1 in the y direction. Gloss image ink density data D ^p _y1 of the calculated y-direction are stored in a predetermined storage area.

By performing the above processing for each pixel, the gloss color ink density data in the diffusion color, x direction, and y direction corresponding to the object is calculated in the surface shape in the surface shape initial data. FIG. 14 is an example of the ink density data of the glossy image property in the diffused color, x direction, and y direction in the right region 2 calculated for the object shown in FIG. In the present embodiment, in the right region 2, since the x direction has high image clarity and the y direction has low image clarity and an anisotropic gloss with a rotation angle φ = 90 °, the ink density is as shown in FIG. . In other words, in one pixel which is a unit area of reflection characteristics (BRDF), by determining the ink density of the glossy image property in the diffused color, the x direction, and the y direction, the glossiness differs in the image clarity and color developability depending on the observation direction. Print data capable of recording anisotropy with high accuracy can be generated. The calculated diffused color ink D ^p _d1 at the pixel p, the gloss image ink D ^p _{x1 in} the x direction, and the gloss image ink data D ^p _{y1 in} the y direction are used as the ink density data D ^p ₁ and the ink density data holding unit 307. Is remembered.
<Operation of Surface Shape Data Deriving Unit 305>
Below, the detail of the surface shape data derivation | leading-out process of step S405 is demonstrated. In this embodiment, since it is difficult to record the surface shape of the satin embroidery formed by the texture structure of the embroidery thread having a thickness of several tens of μm with an image recording apparatus, And surface shape data representing the gloss anisotropy.

The surface shape data deriving unit 305 acquires the surface shape initial data H ^p ₀ acquired by the surface shape initial data acquiring unit 302. Further, the surface shape data deriving unit 305 derives the surface shape data from the data indicating the divided ink application region, the derived ink density data, and the surface shape initial data according to the following equation (16). .

Expression (14) calculates surface shape data in which the difference between the reflection characteristic (I _brdf ) of the reflection characteristic data input in step S401 and the reflection characteristic (I ′ _brdf ) obtained from each of the data is small. . Of the parameters of equation (16), the difference from equation (10) is the ink density data. The other parameters are the same as those described in Expression (10). In equation (1), the ink density data is fixed to the ink density data D ^p ₁ derived in step S404. Then, the surface shape data H ^p is calculated by using the surface shape initial data H ^p ₀ as an initial value and using a known optimization algorithm such as a gradient method or a quadratic programming method. The calculated surface shape data H ^p is stored in a predetermined storage area.

  By performing the above processing for each pixel, surface shape data for each pixel of the object is derived. FIG. 15A is an example of the surface shape data of one pixel in the right region 2 of the derived object of FIG. In the present embodiment, the right region 2 has high gloss in the x direction and low gloss in the y direction and has an anisotropic gloss with a rotation angle φ = 90 °. Therefore, the half width in the x direction is narrow, The height data follows a distorted Gaussian distribution with a wide half-value width. The derived surface shape data H is stored in the surface shape data holding unit 308. The derived surface shape data H is acquired by the surface shape initial data acquisition unit 302 as the surface shape initial data in the subsequent iterative calculation.

  In this embodiment, in order to record both gloss anisotropy and diffuse color with high accuracy, the surface shape data, ink application region, and ink density data calculation processes described above are repeatedly performed for each pixel of the reflection characteristic data. . FIG. 15B shows the surface shape data of one pixel derived by the iterative calculation process in steps S402 to S406. FIGS. 15C to 15E show one-pixel ink application areas in the right area 2 of the satin embroidery shown in FIG. As shown in FIG. 15B, the ink application area is in accordance with a distorted Gaussian distribution having a narrow half width in the x direction and a wide half width in the y direction. FIG. 16 shows ink density data in each ink application region corresponding to FIGS. 15E to 15E in the right side region 2 of the satin embroidery derived by the repetitive calculation processing.

  By calculating the surface shape data, ink application area, and ink density data described above for each pixel of the reflection characteristic data, gloss anisotropy with different image clarity and color developability can be recorded with high accuracy. can do.

  In this embodiment, satin embroidery is used for the object. However, the object is not particularly limited as long as it has anisotropic reflection, such as a metal plate subjected to hairline processing. Further, although the satin embroidery having a substantially planar shape is used for the object, an object having a three-dimensional shape may be used, and the shape of the object is not particularly limited to a plane.

  In this embodiment, an anisotropic Ward model parameter is used as input reflection characteristic data. However, any model parameter indicating gloss anisotropy, such as an Ashikmin microfacet model, may be used, and the present invention is particularly limited to the anisotropic Ward model. Not what you want. Further, although it is assumed that the reflection characteristic data is input as two-dimensional image information obtained by synchronizing the above 13 channels of 8-bit floating point, it is needless to say that the present invention is not limited to this.

  In this embodiment, height data according to the Gaussian distribution is input as the surface shape initial data. However, a look-up table in which the surface shape data for the reflection characteristic data of the object is stored in advance may be referred to. It is not intended to limit. Further, the surface shape data constituted by the height information of 29 × 29 lattice points L per one pixel of the reflection characteristic data is derived, but the resolution of the surface shape data is not particularly limited. Further, the surface shape data of the adjacent pixel boundary may be averaged in order to prevent a shape step due to a difference in the surface shape data at the adjacent pixel boundary of the reflection characteristic data and the accompanying shadow.

  Further, the recording method of the printer 210 and the type of ink are not limited to those described in this embodiment.

[Example 2]
In the first embodiment, the method of recording the gloss anisotropy of the satin embroidery with high accuracy by dividing the ink application region in the surface shape and applying the divided regions with different ink densities has been described. It is difficult to record the surface shape of the satin embroidery formed by the texture structure of the embroidery thread having a thickness of several tens of μm with an image recording apparatus with high accuracy. Therefore, in the first embodiment, regarding the surface shape data of the satin embroidery, the example in which the surface shape data expressing the gloss anisotropy is calculated according to the above-described equation (16) has been described. That is, for the surface shape data, the example in which the surface shape data having the reflection characteristics close to the input reflection characteristics is derived by the optimization process has been described. In this embodiment, a method for recording gloss anisotropy caused by a low-frequency surface shape of about several hundred μm formed by the touch of an oil painting brush with high accuracy will be described. Since the surface shape with a low frequency of about several hundred μm can be recorded with high accuracy by the image recording apparatus, the surface shape data of the oil painting obtained by the existing shape obtaining method is input as the surface shape data. Further, a method for recording both the oil painting shape and gloss anisotropy with high accuracy by deriving the ink application area and the ink density data according to the input surface shape data will be described.

  In the present embodiment, as in FIG. 1 of the first embodiment, a horizontal streak surface shape is formed in the left region 1 by the touch of the brush, and a vertical streak surface shape is formed in the right region 2. Shall be formed.

  FIG. 17 shows a block diagram of the image recording apparatus in the present embodiment. The contents other than the surface shape initial data acquisition unit 302 and the surface shape data derivation unit 305 are the same as those described in the first embodiment with reference to FIG. Hereinafter, the details of the block diagram of the image recording apparatus in the present embodiment will be described with reference to FIG. A surface shape data input unit 1701 inputs surface shape data of an object. The input surface shape data is output to the ink application region dividing unit 303, the surface shape data holding unit 308, and the ink density data deriving unit 304. Since others are the same as those of the first embodiment, the description thereof is omitted.

  FIG. 18 is a flowchart showing an image recording method in this embodiment. Except for steps S402, S405, and S406, the contents are the same as those described in the first embodiment with reference to FIG. The details of the image recording method in this embodiment will be described below with reference to FIG. For the sake of simplicity, it is assumed that the data shown in FIG. 5 of the first embodiment is input as the reflection characteristic data input in step S401 of the present embodiment.

  In step S1801, the surface shape data input unit 1701 inputs the surface shape data of the object. In this embodiment, as in the first embodiment, 8-bit image data composed of height information of 29 × 29 lattice points L arranged in a matrix in one pixel of the reflection characteristic data is used as the surface shape data. FIG. 19A shows surface shape data in one pixel in the right region 2 of the object as shown in FIG. 1, and the height according to the surface shape distribution in the vertical direction formed by the touch of the brush. have. The input surface shape data is stored in the surface shape data holding unit 308. In step S1902, whether or not the reflection characteristic data of the printed matter derived from the ink application area, ink density data, and surface shape data represents the reflection characteristic data of the object is determined according to the above-described equation (3). When the expression (3) is satisfied for all the pixels, it is determined that the ink application region, the ink density data, and the surface shape data representing the reflection characteristics of the object have been calculated, and the process proceeds to step S407. If there is a pixel that does not satisfy Expression (3), the process returns to step S403 and the derivation process is repeated. FIGS. 19B to 19D show each ink application area in one pixel in the right area 2 of the oil painting derived in this embodiment, and FIG. 19E shows ink density data of each ink application area. It is. In accordance with the input surface shape data, ink application area and ink density data expressing the gloss anisotropy of the oil painting are calculated. Since other processes are the same as those in the first embodiment, description thereof is omitted.

  By performing the ink application area and ink density data calculation process according to the input surface shape data, it is possible to record both the shape of the oil painting and the gloss anisotropy with high accuracy.

<Other examples>
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Reflection characteristic data input unit 301
Ink application area dividing unit 303
Ink density data deriving unit 304
Surface shape data deriving unit 305
Image recording unit 310

Claims (16)

A print data generation device for generating print data for reproducing an object having gloss anisotropy,
Input means for inputting reflection characteristic data indicating the reflection characteristic of the object to be reproduced;
A dividing unit that divides a region where ink is applied into a plurality of regions expressing gloss anisotropy according to the reflection characteristics;
Density data deriving means for deriving density data indicating the density of ink applied to each of the plurality of regions divided by the dividing means according to the reflection characteristics of the object;
A print data generation apparatus comprising: surface shape data deriving means for deriving surface shape data indicating a surface shape of a region to which the ink is applied according to a reflection characteristic of the object.   The dividing unit divides a region where the ink is applied in a surface shape corresponding to surface shape data indicating an arbitrary shape or surface shape data derived by the surface shape data deriving unit. Item 4. The print data generation device according to Item 1.   The print data generation apparatus according to claim 2, wherein the dividing unit divides a region to which the ink is applied in the surface shape data into the plurality of regions expressing the gloss anisotropy.   4. The printing according to claim 3, wherein the dividing unit divides a region to which ink is applied into a region expressing a diffusion color of the object and a plurality of regions expressing the gloss anisotropy. Data generator.   The print data generation apparatus according to claim 4, wherein the dividing unit determines a region having a flat surface shape as a region expressing the diffusion color.   The dividing unit determines a region where the unevenness in the X direction of the region having an uneven surface shape is a region expressing the gloss image property in the X direction, and a region where the unevenness in the Y direction is changed as Y 6. The print data generation apparatus according to claim 4 or 5, wherein the print data generation apparatus determines the area corresponding to the glossy image clarity of the direction.   The density data deriving unit derives, for each of the plurality of areas, density data indicating an ink density at which a reflection characteristic when ink is applied to each area is close to a reflection characteristic of the object to be reproduced. The print data generation apparatus according to claim 1, wherein the print data generation apparatus is a print data generation apparatus.   The shape data deriving unit obtains surface shape data indicating a surface shape of a region to which the ink is applied when the density data derived by the density data deriving unit is applied to each of the plurality of regions. The print data generation apparatus according to claim 1, wherein the print data generation apparatus is derived in accordance with reflection characteristics.   The shape data deriving means includes surface shape data indicating a surface shape in which a reflection characteristic when ink is applied to each of the plurality of regions with the derived ink density is close to a reflection characteristic of the object to be reproduced. The print data generation apparatus according to claim 8, wherein the print data generation apparatus is derived.   Integration of the difference in the predetermined light source / observation direction between the reflection characteristic when ink is applied to each of the plurality of regions at the derived density in the derived surface shape and the reflection characteristic of the object to be reproduced 10. The print data generation apparatus according to claim 1, wherein the dividing unit repeatedly performs processing using the derived surface shape data until a value becomes less than a threshold value. 11. A print data generation device for generating print data for reproducing an object having gloss anisotropy,
Input means for inputting reflection characteristic data indicating the reflection characteristic of the object to be reproduced and surface shape data indicating the surface shape of the object;
A dividing unit that divides a region where ink is applied to the surface shape indicated by the surface shape data into a plurality of regions expressing gloss anisotropy according to reflection characteristics;
Print data generation apparatus, comprising: density data deriving means for deriving density data indicating the density of ink applied to each of the plurality of regions divided by the dividing means according to the reflection characteristics of the object .   12. The apparatus according to claim 1, further comprising output means for outputting print data based on the surface shape data, data indicating the plurality of regions, and the density data to an image recording apparatus. The print data generation device described in 1.   An image recording apparatus that reproduces an object by forming an image based on the print data output from the print data generation apparatus according to claim 1. A print data generation method for generating print data for reproducing an object having gloss anisotropy,
An input step for inputting reflection characteristic data indicating the reflection characteristic of the object to be reproduced;
A division step of dividing an area where ink is applied into a plurality of areas expressing gloss anisotropy according to the reflection characteristics;
A density data deriving step for deriving density data indicating the density of the ink applied to each of the plurality of regions divided by the dividing step according to the reflection characteristics of the object;
And a surface shape data deriving step for deriving surface shape data indicating a surface shape of a region to which the ink is applied in accordance with a reflection characteristic of the object. A print data generation method for generating print data for reproducing an object having gloss anisotropy,
An input step for inputting reflection characteristic data indicating the reflection characteristic of the object to be reproduced and surface shape data indicating the surface shape of the object;
A division step of dividing an area where ink is applied to the surface shape indicated by the surface shape data into a plurality of areas expressing gloss anisotropy according to reflection characteristics;
And a density data deriving step for deriving density data indicating the density of ink applied to each of the plurality of areas divided in the dividing step in accordance with reflection characteristics of the object. .   The program for functioning a computer as each means of the printing data generation apparatus as described in any one of Claims 1-12.